Exhaust gas purification system and controlling method thereof

摘要: A controlling method of exhaust gas purification system to which a lean combustion engine is applied and an LNT device, DPF or SDPF, SCR device are provided includes detecting vehicle information determining whether the satisfies nitrogen oxide desorption condition device; desorbing until reaches predetermined reference amount through rich when injecting urea purify after first period ending LNT; sulfide combustion; second LNT.